Vapor Deposition of Microstructured Silicon-Containing Polymer Films on High Viscosity Silicone Oils

Silicon-containing polymer films can be used as precursors in the fabrication of nanoporous membranes for use in alternative energy applications.[1] We studied the initiated chemical vapor deposition (iCVD) of cross-linked silicon-containing polymer films onto high viscosity silicone oil substrates. 2,4,6,8-tetramethyl cyclotetrasiloxane (V4D4) was used as the monomer and ethylene glycol diacrylate (EGDA) was used as the crosslinker. The formation of microstructures was observed similar to those seen in our earlier work.[2] We systematically studied the change in the microstructure morphology and the chemical composition of the copolymer films at different V4D4 to EGDA flow ratios of 1.5:1, 1:1, and 1:1.5 and at different silicone oil viscosities of 500, 1000, and 10000 centistokes. Quartz crystal microbalance was used to analyze the absorbance of the precursors into the silicone oil substrates, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy were used to measure the chemical compositions of the films, and scanning electron microscopy was used to analyze the microstructure morphology.

[1] Nguyen, B., Dabir, S., Tsotsis, T., Gupta, M. Fabrication of Hydrogen-Selective Silica Membranes via Pyrolysis of Vapor Deposited Polymer Films,” Industrial & Chemical Engineering Research, 58, pp. 15190-15198 (2019).

[2] Bradley, L. C. and M. Gupta, “Microstructured Films Formed on Liquid Substrates via Initiated Chemical Vapor Deposition of Cross-Linked Polymers,” Langmuir, 31, pp. 7999-8005 (2015).